1. Field of the Invention
The present invention is generally in the field of electronics. More particularly, the present invention is in the field of analog to digital converters and devices using same.
2. Background
Portable electronic devices, such as cellular telephones, typically determine the power remaining in their power source, such as a battery, by measuring the output current or voltage of the power source. For example, the output voltage of the power source can be divided down using a voltage divider and the divided output voltage can be provided to the input of an analog to digital converter to generate a digital output value corresponding to the output voltage of the power source. The digital output value can be used by the electronic device to estimate the power or energy remaining in the power source. Thus, the accuracy of the digital output value generated by the analog to digital converter is critical for accurate estimation of the power remaining in the power source.
However, the output voltage from the power source can vary significantly during the operation of the electronic device or even during times when the electronic device is idle. For example, large fluctuations in the output current of the power source, high radio frequency (“RF”) noise, and various digital noise in the electronic device can cause the divided voltage sampled by the analog to digital converter to undesirably fluctuate. Thus, the analog to digital converter can generate inaccurate digital output values, which can undesirably result in inaccurate approximations of the power remaining in the power source.